There are many stages in the conventional production process or "imaging chain" that begins with the manufacture of motion picture and television film and culminates in the production of feature films, television programs, and commercials. Apparatus that handle film at various stages of this process include numerous types of cameras, film magazines, photoprocessing equipment, editing equipment (including special effects), telecine machines, and intermediate and final film printing apparatus. The production process also requires, at several stages throughout the imaging chain, the input of creative and technical individuals who add value to the film content throughout the entire pre-production, production, and post-production process. Consequently, there is a desire to provide improved methods for communication between the people involved in various stages of the film production process, whereby useful information for film processing may be conveniently exchanged.
Scene information is initially recorded in a photographic film by exposing an origination film (e.g., a camera color negative film). Color negative films are a class of photosensitive materials that (after photographic development) map the luminance (neutral) and chrominance (color) information of a scene to complementary tonal and hue polarities in the negative film. Light areas of the scene are recorded as dark areas on the color negative film, and dark areas of the scene are recorded as light areas on the color negative film. Colored areas of the scene are recorded as complementary colors in the color negative film: red is recorded as cyan, green is recorded as magenta, blue is recorded as yellow, etc. In order to render an accurate reproduction of a scene, a subsequent process is necessary to reverse the luminance and chrominance information back to those of the original scene. This subsequent process may or may not require another photosensitive material. In the motion picture industry, there are two common subsequent processes. One such subsequent process is to optically print (by contact or optics) the color negative film onto another negative working photosensitive material, such as Eastman Color Print Film 5386.TM., to produce (after photographic development) a color positive image suitable for projection, or an intermediate film to produce a master positive, which may be used to subsequently produce a duplicate negative by again printing on an intermediate film. Another subsequent process in the motion picture industry is to transfer the color negative film information directly into a video signal using a telecine transfer device, or indirectly by first making a positive photographic print and then transferring the print film information into a video signal using such a device. Various types of telecine transfer devices are described in Engineering Handbook, E. O. Fritts, Ed., 8th edition, National Association of Broadcasters, 1992, Chapter 5.8, pp. 933-946, the disclosure of which is incorporated by reference. The most popular of such devices generally employ either a flying spot scanner using photomultiplier tube detectors, or arrays of charged-coupled devices, also called CCD sensors. Telecine devices scan each negative or positive film frame transforming the transmittance at each pixel of an image into voltage. The signal processing then inverts the electrical signal in the case of a transfer made from a negative film in order to render a positive image. The signal is carefully amplified and modulated, and fed into a cathode ray tube monitor to display the image reproduction, or recorded onto magnetic tape for storage. Prior to or after such subsequent processes, films with recorded scene images may be subjected to various additional processing steps, including editing and special effects addition.
There are a number of conventional methods for communicating between different individuals who are responsible for film processing at various stages in the imaging chain. Traditionally, an assistant cameraman (AC) prepares a written camera report that includes production information such as footage counts for scenes and takes, identification of acceptable takes, framing, film type and emulsion, lighting temperature, filtration, T-stop, camera frame rate, special processing requests, color balance, telecine transfer preferences and similar related information. The written camera report is typically provided in duplicate, with a copy retained by the AC as a backup record, and a copy or copies attached to the film canister that contains the exposed, but undeveloped film. This written camera report is ultimately used by the processing lab. This report typically goes to a color timer if the negative is printed after processing and may alternately go to a colorist if the negative is to be transferred using a telecine device.
Conventional hand-written camera reports of this type are widely used and provide the basic information needed for efficient processing of the film. However, there are a number of disadvantages to these reports. Legibility and clarity can easily vary from one report to another. More importantly, a report can become separated from the film canister to which it is originally attached. This could mean loss of valuable information or even the wrong information provided for a particular reel of film. Furthermore, report information is typically limited to camera and capture (exposure) information. Other data typically not provided in the report could be useful in subsequent film processing, such as film sensitometry, film manufacture ID, and emulsion data.
As another alternative method for communication of film and processing data, some motion picture camera manufacturers offer a laptop camera controller (LCC) for remote control of camera operation such as exposure control, shutter angle transport speed and accounting report generation. The LCC can be used to generate manual or automatic camera report information in an electronic file (e.g. ASCII, Windows NT) which can then be printed, faxed or electronically transferred to processing and post production facilities. In many ways, this system provides a good alternative to hand-written camera reports. However, with this alternate method, the digitally encoded information is not attached to the film, but takes a different path to arrive at the film processing facility. Moreover, the electronic file that is provided gives information up to the point where the film is exposed in the camera. Relative to the overall imaging chain, there is no further modification of this file data after it is transferred to the production lab.
Film manufacturers provide yet another alternative method for communicating information relevant to film processing using a "keycode". Written near the edge of the film, a human- and machine-readable alphanumeric and barcode system provides information on film code and emulsion identification, and provides footage and frame counts corresponding to the images on the film. An industry standard for this keycode system exists and this system is conventionally used in the motion picture production chain. The keycode information is written in the photosensitive layers near the edge of the film according to SMPTE (Society of Motion Picture and TV Engineers) specification using a laser or light emitting diode (LED) device. The latent keycode image is developed during film processing into either an optical human-readable or machine-readable barcode. This keycode information can then be used in the editing, color timing and telecine transfer processes to identify and select frame positions for splicing, color timing changes such as printer light changes and fades and dissolves, and sound synchronization points in an on-line or off-line editing system.
The keycode system, since it follows an industry standard, is well-known in motion picture processing and provides very valuable information for the editing and color timing processes. This system is very useful for providing a frame search, identification and orientation process to make reliable and accurate cuts when performing on-line, off-line and final negative cutting edits. Furthermore, with the manufacturer's ID information incorporated into the keycode, tracking information is retained in the film should it be necessary in the future. However, relative to the overall imaging chain, this system has its limitations. The main disadvantage of the keycode system is that its information is limited to film code, film emulsion, and footage and frame count information. The system does not provide a means to communicate technical and artistic information from a film cinematographer to a processing lab, color timer, colorist, or telecine operator.
Timecode systems also provide some of the information useful to motion picture film photoprocessing. Originally developed for the video market, timecode methods have been implemented to allow for simpler post production sound and image synchronization, especially for multi-camera film capture. Conventional systems of this type include both standard timecode systems such as the SMPTE and proprietary systems such as Aatoncode.TM. (Aaton, Inc., Grenoble, France) and FIS.TM. (Arri, Munich, Germany). While these systems are not identical, they all operate on the same basic principle, keeping very accurate real or relative time synchronization when using multiple cameras and audio and video tape recorders. For film, these systems write a machine-readable code that synchronizes each frame of a motion picture negative. Some timecode systems also periodically write reference marks and human-readable timecode to the film. This reference, written to the image layers of the film by an LED or similar type of device, becomes a permanent part of the negative film once it is developed. Both the machine- and human-readable timecoded images can thereby be used in the editing process, making it easier to find and edit together sound and images recorded from different devices.
Disadvantages of timecode systems include their inability to record information other than time and frame counts. For example, using a timecode system, such data as camera, exposure, lighting conditions and other information must still be provided on a hand-written camera report. Emulsion data and manufacturing information is not available with this method of data encoding. Furthermore, because the timecode information is written in an optical fashion to the photosensitive layer of the film, any data provided using this encoding method is not available, in either human- or machine-readable form, until the film is developed. Thus, while timecode information is available for post production processes such as color timing and telecine transfer, it is not available as an input for the lab processing stage.
Magnetics On Film (MOF) techniques have been used successfully for information storage in some types of consumer film applications. Using MOF technology, a magnetic layer is provided in the manufacturing process of the film support. This layer, usually containing some type of iron oxide or other metal oxide, provides a medium in which information can be stored. By incorporating magnetic heads in cameras, processors, telecine apparatus, and other processing equipment, information pertinent to the film image capture, such as that included in camera reports, can be written to the film. This machine-readable information can then be accessed from downstream magnetic readers for use in post-production processes.
MOF methods present an alternative for incorporating both camera report and time-code and footage frame count information directly onto the film. However, MOF systems are complex to manufacture and are therefore costly. MOF use requires manufacture of the film support (base) in a manner that is substantially more complex than is used in present manufacturing systems. Additionally, use of MOF technology requires that numerous manufacturers incorporate magnetic read/write heads on various equipment used throughout the production and post production processes. For these reasons, MOF is not an economically viable system for motion picture manufacture.
Still another method for communicating film information includes providing information in the form of reference exposures on the film itself. For example, a cinematographer may record a reference exposure in a color negative film image using the motion picture camera in order to communicate exposure and/or color timing information to a colorist or color timer. Typically, such information is often limited to lighting conditions, exposure, and reference exposure conditions. This system can communicate some information to a colorist. However, this method does not eliminate the need for supplemental verbal or written communication, such as to alert the colorist or color timer that information is incorporated in a specific image field and in a specific roll, for example.
Other limited methods are also available which provide some information for film processing. A cinematographer may record special instructions to a colorist or color timer via an audio cassette recorder. This system is not widely used as it requires audio cassette playback capability and is susceptible to the many quality problems associated with small and handheld audio cassette recorders. U.S. Pat. No. 5,642,285 (Woo et al) teaches the use of a Global Position Satellite (GPS) navigation receiver for communicating frame-by-frame camera position estimates and timecode information for use in filming special effects. However, this method is restricted to timecode information and does not provide for user specified input fields to incorporate image information for communication during the production and post production processes. U.S. Pat. No. 4,938,585 (Weiffenbach et al) teaches the use of an image pulse generator mounted in a camera to record information about an image electro-optically onto the camera negative film and a reference signal identifying the image for which information was recorded. The subsequent information is then accessed in an auxiliary memory database. This method provides only a limited amount of bit storage for user specified fields other than timecode information and also requires expensive auxiliary data storage and access devices in the post production equipment.
The best method for providing information about the motion picture film would support the additive operations of numerous individuals who contribute to the development of the film throughout various stages of the imaging chain.
As noted above, none of the conventional methods used meet all of these requirements: (a) supports each process in the imaging chain, from manufacture, to image capture, to film development and printing, to post-production processing, allowing information to be used and updated at any stage in the chain and transmitted to subsequent stages; (b) provides data integrally attached to the film or film carrier, to prevent loss of the information; (c) allows contactless access to information; (d) does not require information written onto the film itself; and (e) is economically feasible, working with existing equipment infrastructure with little required modifications.
It can be seen, therefore, that there is a need for an efficient method for storing and transferring information about photographic film processing at each stage in the imaging chain, especially for motion picture film productions.